There are ways of showing that you are probably being honest in such situations and thereby making yourself more credible than those that are not. Viz. setting out your own weaknesses. For example, in business plans for investors this can be done in a SWOT analysis (which includes listing weaknesses and threats, as well as how you aim to deal with them).
People who claim to have no weaknesses, or at least do not mention any, or who only admit to slight weaknesses (and not to obvious larger ones), lack credibility.
There are ways of showing that you are probably being honest in such situations and thereby making yourself more credible than those that are not. Viz. setting out your own weaknesses. For example, in business plans for investors this can be done in a SWOT analysis (which includes listing weaknesses and threats, as well as how you aim to deal with them).
People who claim to have no weaknesses, or at least do not mention any, or who only admit to slight weaknesses (and not to obvious larger ones), lack credibility.